//   OData .NET Libraries
//   Copyright (c) Microsoft Corporation. All rights reserved.  
//   Licensed under the Apache License, Version 2.0 (the "License");
//   you may not use this file except in compliance with the License.
//   You may obtain a copy of the License at

//       http://www.apache.org/licenses/LICENSE-2.0

//   Unless required by applicable law or agreed to in writing, software
//   distributed under the License is distributed on an "AS IS" BASIS,
//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//   See the License for the specific language governing permissions and
//   limitations under the License.

namespace Microsoft.OData.Core.UriParser.Parsers
{
    using System.Collections.Generic;
    using Microsoft.OData.Core.UriParser.Syntactic;

    /// <summary>
    /// Combine a top level select and expand token.
    /// </summary>
    internal static class SelectExpandSyntacticUnifier
    {
        /// <summary>
        /// Combine a top level select and expand token
        /// </summary>
        /// <param name="expand">the original expand token</param>
        /// <param name="select">the original select token</param>
        /// <returns>A new ExpandToken with the original select token embedded within a new top level expand token.</returns>
        public static ExpandToken Combine(ExpandToken expand, SelectToken select)
        {
            // build a new top level expand token embedding the top level select token.
            ExpandTermToken newTopLevelExpandTerm = new ExpandTermToken(new SystemToken(ExpressionConstants.It, null), select, expand);
            return new ExpandToken(new List<ExpandTermToken>() { newTopLevelExpandTerm });
        }
    }
}
